The present invention relates to a device for separation of constituents, separable in a filter, from a liquid medium containing such constitutents, comprising a stack of a plurality of cells, each one containing at least one filter, one inlet for supply of a liquid medium on one side of the filter, one outlet for discharging part of the liquid medium--the reject--on the same side of the filter, one outlet for discharging liquid medium which has passed through the filter--the permeate--on the other side of the filter, and a rotor arranged on the first side of the filter and having parts which are movable along the surface of the filter.
A device of the above-mentioned kind is described in the U.S. Pat No. 4,740,312.